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Finding the Fourth Proportional to 253.98, 380.72 and 138.40

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Solution

The fourth proportional to 253.98, 380.72 and 138.40 is: 207.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    253.98 : 380.72 = 138.40 : x
  2. Step 2: Convert to fraction form
    253.98/380.72 = 138.40/x
  3. Step 3: Cross multiply
    253.98x = 380.72 × 138.40
  4. Step 4: Simplify right side
    253.98x = 52,689.80
  5. Step 5: Solve for x
    x = 52,689.80/253.98
  6. Step 6: Final answer
    x = 207.45

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.